This invention relates to a process for the liquefaction of air, or of primary air components thereof, by heat exchange with a cycle medium containing nitrogen and hydrocarbons, wherein the cycle medium is, in several stages, cooled and partially condensed, and the liquid portions obtained during the partial condensation are expanded and rewarmed countercurrently to mixture to be cooled, vaporized, and recompressed. By "primary air components" is meant oxygen or nitrogen.
It is conventional in connection with the liquefaction of air or nitrogen to produce the required refrigeration by processes operating in accordance with the Linde or Claude principles. In these processes, especially in the Linde method, large temperature differences are encountered between the cycle medium to be warmed and the cycle medium to be cooled, thereby resulting in exergonic losses. Consequently, these processes have the disadvantage of a large specific energy consumption. To avoid this disadvantage, it is known (Leiden Communications, Supplement No. 76a) to utilize single-component cascaded cycles for refrigeration production. Such a process, while resulting in a low specific energy consumption, requires a separate compressor and ancillary apparatus for each cycle of the cascade, thereby requiring an extremely high capital outlay for such a plant.